Consolidated Statements of Equity and Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	Total	Common Stock	Paid-In Capital	Retained Earnings	Accum. Other Comprehensive Income (Loss)	Common Stock In Treasury	SPX Corporation Shareholders' Equity	Noncontrolling Interests	Comprehensive Income (Loss)
Balance at Dec. 31, 2008	$ 2,024.8	$ 972.3	$ 1,393.9	$ 2,220.5	$ (179.9)	$ (2,416.0)	$ 1,990.8	$ 34.0
Increase (Decrease) in Shareholders' Equity
Net income	16.2			31.7			31.7	(15.5)	16.2
Net unrealized gain (loss) on qualifying cash flow hedges, net of tax of $0.7, $10.8 and $6.7 in 2011, 2010 and 2009, respectively	10.9				10.9		10.9		10.9
Pension liability adjustment, net of tax of $7.7, $1.4 and $56.5 in 2011, 2010 and 2009, respectively	(95.2)				(95.2)		(95.2)		(95.2)
Foreign currency translation adjustments, including $5.7 of translation gains recognized upon sale of discontinued operations in 2009	51.4				50.6		50.6	0.8	51.4
Total comprehensive income (loss)	(16.7)								(16.7)
Dividends declared ($1.00 per share)	(49.2)			(49.2)			(49.2)
Exercise of stock options and other incentive plan activity, including related tax benefit of $1.1, $3.2 and $1.7 in 2011, 2010 and 2009, respectively	25.2	5.0	20.2				25.2
Amortization of restricted stock and restricted stock unit grants (includes $0.1 recorded to discontinued operations in 2009)	27.7		27.7				27.7
Restricted stock and restricted stock unit vesting, net of tax withholdings	(6.7)	1.7	(14.3)			5.9	(6.7)
Treasury stock repurchased	(113.2)					(113.2)	(113.2)
Dividends attributable to noncontrolling interests	(0.4)							(0.4)
Liquidation of noncontrolling interest due to disposition of Filtran (See Note 4)	(5.1)							(5.1)
Purchase of subsidiary shares from noncontrolling interest	(3.0)		(1.8)				(1.8)	(1.2)
Other changes in noncontrolling interests	(1.9)							(1.9)
Balance at Dec. 31, 2009	1,881.5	979.0	1,425.7	2,203.0	(213.6)	(2,523.3)	1,870.8	10.7
Increase (Decrease) in Shareholders' Equity
Net income	202.8			205.6			205.6	(2.8)	202.8
Net unrealized gain (loss) on qualifying cash flow hedges, net of tax of $0.7, $10.8 and $6.7 in 2011, 2010 and 2009, respectively	17.4				17.4		17.4		17.4
Net unrealized gain (loss) on available-for-sale securities	6.1				6.1		6.1		6.1
Pension liability adjustment, net of tax of $7.7, $1.4 and $56.5 in 2011, 2010 and 2009, respectively	28.9				28.9		28.9		28.9
Foreign currency translation adjustments, including $5.7 of translation gains recognized upon sale of discontinued operations in 2009	(31.1)				(31.4)		(31.4)	0.3	(31.1)
Total comprehensive income (loss)	224.1								224.1
Dividends declared ($1.00 per share)	(50.0)			(50.0)			(50.0)
Exercise of stock options and other incentive plan activity, including related tax benefit of $1.1, $3.2 and $1.7 in 2011, 2010 and 2009, respectively	31.4	5.1	26.3				31.4
Amortization of restricted stock and restricted stock unit grants (includes $0.1 recorded to discontinued operations in 2009)	31.1		31.1				31.1
Restricted stock and restricted stock unit vesting, net of tax withholdings	(12.2)	2.6	(22.0)			7.2	(12.2)
Dividends attributable to noncontrolling interests	(2.6)							(2.6)
Other changes in noncontrolling interests	0.7							0.7
Balance at Dec. 31, 2010	2,104.0	986.7	1,461.1	2,358.6	(192.6)	(2,516.1)	2,097.7	6.3
Increase (Decrease) in Shareholders' Equity
Net income	185.6			180.6			180.6	5.0	185.6
Net unrealized gain (loss) on qualifying cash flow hedges, net of tax of $0.7, $10.8 and $6.7 in 2011, 2010 and 2009, respectively	(1.1)				(1.1)		(1.1)		(1.1)
Net unrealized gain (loss) on available-for-sale securities	(7.6)				(7.6)		(7.6)		(7.6)
Pension liability adjustment, net of tax of $7.7, $1.4 and $56.5 in 2011, 2010 and 2009, respectively	(21.7)				(21.7)		(21.7)		(21.7)
Foreign currency translation adjustments, including $5.7 of translation gains recognized upon sale of discontinued operations in 2009	(23.6)				(23.5)		(23.5)	(0.1)	(23.6)
Total comprehensive income (loss)	131.6								131.6
Dividends declared ($1.00 per share)	(50.9)			(50.9)			(50.9)
Exercise of stock options and other incentive plan activity, including related tax benefit of $1.1, $3.2 and $1.7 in 2011, 2010 and 2009, respectively	29.0	4.3	24.7				29.0
Amortization of restricted stock and restricted stock unit grants (includes $0.1 recorded to discontinued operations in 2009)	41.4		41.4				41.4
Restricted stock and restricted stock unit vesting, net of tax withholdings	(16.6)	2.6	(25.0)			5.8	(16.6)
Dividends attributable to noncontrolling interests	(4.1)							(4.1)
Other changes in noncontrolling interests	2.9							2.9
Balance at Dec. 31, 2011	$ 2,237.3	$ 993.6	$ 1,502.2	$ 2,488.3	$ (246.5)	$ (2,510.3)	$ 2,227.3	$ 10.0